Lifestyle interventions, while effective at reducing weight and diabetes risk, are intensive (i.e., requiring 16 or more face-to-face visits) which has prevented widespread implementation. Mobile technology may reduce intervention intensity while preserving outcomes by assisting in the delivery of behavioral strategies, but very little research has explored this. Weight loss mobile applications are proliferating in the open market; however our work and others2 show that the range of evidence-based strategies addressed by these apps is narrow, primarily including self-monitoring, prompts, goal-setting, and sometimes a social network.3 A key strategy missing across apps in both the market and research is problem solving, an essential component of behavioral weight loss interventions.4 We propose to develop and test the feasibility of Smart Coach, a weight loss mobile application that includes common features such as self-monitoring, goal setting, and a social network, but even more importantly, an avatar-facilitated, idiographic problem solving feature that processes information intelligently to help patients identify solutions to their weight loss problems. We hypothesize tha Smart Coach when combined with a lower intensity (half the sessions) weight loss intervention will be more effective than a lower intensity weight loss intervention alone, with biggest differences observable after face-to- face visits end. Using a crowd-sourcing model, we will populate a database with problems and solutions via 1) expert-delivered problem solving sessions with a sample of obese participants trying to lose weight and 2) a pre-pilot test of the app. Using principles of artificial intelligence we will convert the algorithm of problem solving counseling into the mobile application so that it may perform this strategy on its own, but based on expert and crowd-sourced information. We will then use a series of iterative steps involving qualitative research methods (usability testing, focus groups, and pre-piloting) to refine the tool A randomized pilot feasibility trial will test the feasibility and initial effects of the Smart Coah mobile application when paired with a shortened (8- week) behavioral weight loss intervention relative to a shortened behavioral weight intervention alone. Feasibility outcomes include frequency and duration of usage of the mobile app and each feature, recruitment, and retention. We will also do exploratory analyses comparing conditions on problem solving skills and weight loss at 8- and 16-weeks. Data will support a larger efficacy trial of a Smart Coach-assisted brief behavioral weight loss intervention relative to a brief behavioral weight loss intervention alone. Our overarching goal is to develop mobile technology that reduces the intensity of lifestyle interventions as far as possible while preserving weight loss outcomes, to ultimately broaden the reach to people and settings that currently have little access.